Chuck jaw stopping mechanism

ABSTRACT

A chuck jaw stopping mechanism is disclosed for forming a soft jaw for a lathe. An example of the chuck jaw stopping mechanism includes a stopping device. The example chuck jaw stopping mechanism also includes a securement device configured to connect the stopping device on a master jaw of a chuck of the lathe. The example chuck jaw stopping mechanism also includes a lower surface of the stopping device that moves against a portion of an outer circumference of the chuck in a closed position. The lower surface also moves away from the portion of the outer circumference of the chuck in an open position to form a gap between the lower surface of the stopping device and the portion of the outside circumference of the chuck.

PRIORITY CLAIM

This application claims the priority filing benefit of U.S. ProvisionalPatent Application No. 63/198,565 filed Oct. 28, 2020 for “Chuck JawStopping Mechanism” of Bradley D. O'Connell, hereby incorporated byreference in its entirety as though fully set forth herein.

BACKGROUND

A lathe is a machine used in manufacturing to make parts out of anunfinished workpiece often referred to as a slug or bar or casting. Theunfinished workpiece may be any material that is machinable by thelathe. During the machining operation, the unfinished workpiece isclamped or otherwise held on the lathe. The lathe spins or rotates theunfinished workpiece. A cutting tool removes material from theunfinished workpiece to create a finished workpiece (e.g., the partbeing made or manufactured).

The lathe includes a chuck to clamp the workpiece. The chuck isconfigured to rotate about a centerline or axis of rotation of theworkpiece. The chuck typically has multiple jaws that move in an inwarddirection to a closed position for clamping, and an outward direction toan open position for unclamping.

Some chucks may have “hard jaws” that clamp the workpiece in place.Other chucks may have “soft jaws” or “machinable jaws.” For a soft ormachinable jaw, a soft machinable material is bolted to the master jaw(e.g., using a T-nut to hold it securely in place). A chuck with a softjaw may be used when more precision is required to hold the centerlineof the workpiece closer to the axis of rotation. A chuck with a soft jawmay also be used when the jaw is machined to a specific diameter tomatch the workpiece that it is gripping. This can help in many ways. Forexample, no clamping marks are left on the finished workpiece. Inaddition, the soft jaw provides more surface area of contact, therebysubstantially increasing concentricity of the workpiece.

Example use of a soft jaw involves clamping a piece of material(clamping plug) in the soft jaws behind where these will be turned. Butthere are two problems with this. One problem is this technique does notwork where the soft jaw cannot be bored all the way through. Anotherproblem is it can be difficult to mount the workpiece straight orparallel when clamping a short or thin workpiece. If the clamping plugdoes not run parallel, it puts uneven pressure on the jaws and causesthe finished part to not be parallel.

Another device is a clamping ring that locates in counterbored holes inthe face of the soft jaws. This allows the jaws to be bored through. Butthe boring tool has to be extended out to allow for clearance, whichcauses other problems. For example, when a boring tool is extended, thetool tends to vibrate (known in the industry as “chatter”). Thisvibration or chatter results in poor finishes and less accuracy in thefinished workpiece. In addition, the clamping ring can be in the way(e.g., out in front) of the working area, and thus does not allow forboring out larger diameters in the workpiece.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an example chuck jaw stopping mechanismas it may be implemented with a lathe.

FIG. 2 is a partially exploded view of the example chuck jaw stoppingmechanism on a lathe.

FIG. 3 is a side-by-side view of example T-nuts.

FIGS. 4 and 5 illustrate assembly of the example chuck jaw stoppingmechanism on a lathe.

FIGS. 6-8 illustrate an example setup operation with the example chuckjaw stopping mechanism on a lathe.

FIG. 9 shows the example chuck jaw stopping mechanism setup on a latheand ready for a soft jaw machining operation.

FIG. 10 shows the example chuck jaw stopping mechanism setup on a latheof FIG. 9 after the soft jaw machining operation.

FIG. 11 shows the example chuck jaw stopping mechanism setup on a lathewith the soft jaws ready for a machining operation on a workpiece.

DETAILED DESCRIPTION

A chuck jaw stopping mechanism is disclosed for forming a soft jaw for alathe. An example of the chuck jaw stopping mechanism includes astopping device. The example chuck jaw stopping mechanism also includesa securement device configured to connect the stopping device on amaster jaw of a chuck of the lathe. The example chuck jaw stoppingmechanism also includes a lower surface of the stopping device thatmoves against a portion of an outer circumference of the chuck in aclosed position. The lower surface also moves away from the portion ofthe outer circumference of the chuck in an open position to form a gapbetween the lower surface of the stopping device and the portion of theoutside circumference of the chuck.

Once installed on the lathe, the chuck jaw stopping mechanism stops allof the master jaws uniformly at a predetermined position for the jawforming operation. This helps maintain a uniform pressure on the softjaws during the jaw forming operation, and holds the soft jawsconcentric in the axis of rotation so that the operator can properlymachine or form the soft jaws to the specific shape that is needed tohold a workpiece during later machining operations.

In an example, the chuck jaw stopping mechanism may be implemented toform soft jaws to a precise specification without needing a separatetool to hold the soft jaws in place that would otherwise get in the wayof the working area. The chuck jaw stopping mechanism also eliminatesthe need for multiple (e.g., hundreds) of different size clamping plugs.The chuck jaw stopping mechanism is quick and easy to use, accurate, andcompact.

Once set up, the chuck jaw stopping mechanism can be removed while thesoft jaws maintain position for the jaw forming operation. As such,there is nothing to get in the way of machining the soft jaws. All sidesof the soft jaw can be easily accessed during the jaw forming operation,all the way through the inside diameter of the soft jaw, the outsidediameter of the soft jaw, and across the entire front face of the softjaw.

Unlike other devices which require a full counterbore in the face of thesoft jaws, the chuck jaw stopping mechanism allows reuse of soft jawsfor future jobs, thereby extending the working life of the soft jaws.

Before continuing, it is noted that as used herein, the terms “includes”and “including” mean, but is not limited to, “includes” or “including”and “includes at least” or “including at least.” The term “based on”means “based on” and “based at least in part on.”

It is also noted that the examples described herein are provided forpurposes of illustration, and are not intended to be limiting. Otherdevices and/or device configurations may be utilized to carry out theoperations described herein.

FIG. 1 is a perspective view of an example chuck jaw stopping mechanism10 as it may be implemented with a lathe. FIG. 2 is a partially explodedview of the example chuck jaw stopping mechanism 10 on a lathe.

An example of the chuck jaw stopping mechanism 10 includes a stoppingdevice 12 and a securement device 14 configured to connect the stoppingdevice 12 on a master jaw 1 of a chuck 2 of the lathe. The stoppingdevice 12 has a lower surface 16 that makes contact with an outercircumference 3 of the chuck 2 to stop inward travel at a predeterminedposition when closing the chuck 2.

In an example, the lower surface 16 moves away (e.g., as illustrated bythe direction of arrow 5) from the outer circumference 3 of the chuck 2to be in an open position. The open position forms a gap between thelower surface 16 of the stopping device 12 and the outside circumference3 of the chuck 2, e.g., for inserting a machinable part. The lowersurface 16 moves against a portion of the outer circumference 3 of thechuck 2 when in a closed position (e.g., moved fully inward asillustrated by the direction of arrow 4). The chuck is moved into theclosed position to retain the machinable part during a machiningoperation.

In an example, the master jaw(s) 1 of the chuck 2 moves in thedirections of arrows 4 and 5 within a predetermined range of travel 6.In general, it is desired to mount one or more soft jaw 20 in about thecenter of the predetermined range of travel 6 for forming the soft jaw20 during a machining operation. This will allow for the machined softjaw 20 to move into the open position (e.g., in the directionillustrated by arrow 5) for insertion of the unfinished workpiece. Thiswill also allow for the machined soft jaw 20 to move into the closedposition (e.g., in the direction illustrated by arrow 4) to clamp on andapply pressure to the workpiece during a machining operation.

In an example, the stopping device 12 maintains the soft jaw at thispredetermined position within a range of travel 6 during machining ofthe soft jaw 20. That is, the stopping device 12 stops inward movementof the master jaw 1 at the predetermined position for forming the softjaw 20 during a machining operation.

In an example, the stopping device 12 has two arms and the lower surface16 is formed on each of the two arms. The securement device 14 connectsto the master jaw 1 between the two arms of the stopping device 12. Inan example, the securement device 14 may be a bolt that threads into athreaded opening in a T-nut 22 of the master jaw 1, e.g., as can be seenin FIGS. 4-5 .

FIG. 3 is a side-by-side view of example T-nuts 22 and 22′. Toillustrate, the T-nut 22′ is a conventional T-nut that is used to attacha soft jaw to the master jaw 1 of the chuck 1. That is, there is a slot7 formed in the body or face of the chuck 2 that the master jaw 1 slidesinto. There is a slot 8 formed in the master jaw 1 that the T-nut 22′slides into. The soft jaw is attached to the T-nut 22′ by threadedfasteners through openings 21 a, 21 b into threaded openings 28′.

The slots 7 and 8 may be referred to as T-slots because of the shape.The slots 7 and 8 are narrow on the top and have a wider portion on thebottom. The wide portion on the bottom works as a clamping surface sowhen the bolts in the soft jaw are tightened the T-nut 22 clamps ontothe master jaw 1 holding the master jaw 1 and the soft jaw 20 securelyin place.

The modified T-nut 22 can also be slid into the slot 8 of the master jaw1 in this same manner. But the modified T-nut 22 has an extended portion24 with a threaded opening 26 formed therein substantially perpendicularto the openings 28 a and 28 b of the T-nut 22. The stopping device 12 isattached to the T-nut 22 via fastener 14 into threaded opening 26 in themodified T-nut 22. The soft jaw is attached to the T-nut 22 by threadedfasteners through openings 21 a, 21 b into threaded openings 28.

FIGS. 4 and 5 illustrate assembly of the example chuck jaw stoppingmechanism 12 on a lathe using the T-nut 22. In an example, the T-nut 22engages with the master jaw 1 and connects the master jaw 1 to thestopping device 12. The T-nut 22 slidably engages and tightens to themaster jaw 1. The stopping device 12 connects to the T-nut 22. The softjaw 20 is attached to the T-nut 22.

In an example, the extended portion 24 of the T-nut 22 pulls toward thestopping device 12 by operation of the fastener 14. The extended portion24 seats against the stopping device 12 when the soft jaw 20 is locatedat the desired position on the face of the chuck 2 (e.g., substantiallycentered within the range of travel 6 of the master jaw 1).

FIGS. 6-8 illustrate an example setup operation with the example chuckjaw stopping mechanism 10 on a lathe. The operations shown and describedherein are provided to illustrate example implementations. It is notedthat the operations are not limited to the ordering shown. Still otheroperations may also be implemented.

As described above, the example chuck jaw stopping mechanism 10 includesa stopping device 12 and a T-nut 22 that serves to securely fasten thestopping device 12 to the master jaw(s) 1. The T-nut 22 slides into themaster jaw 1. The T-nut 22 can slide in or out so the soft jaw 20 can bemoved into the desired position for machining. When the soft jaw 20 isclamped to the master jaw 1, both the soft jaw 20 and the T-nut 22 areheld in place using the serrations that are in both the master jaws 1and the soft jaws 20. After the T-nut 22 is secured in place thestopping device can then be bolted and secured to the master jaw.

A fastener 14 is inserted through the stopping device 12 and into thethreaded hole 26 in the T-nut 22 to securely fasten the soft jaw 20 tothe master jaw 1 while the lathe chuck 2. While the chuck 2 is in theopen position there is a small gap between the stopping mechanism andthe outside diameter of the chuck 2. When the master jaw 1 is closed,the stopping device 12 contacts the outside perimeter 3 (or portionthereof) of the lathe chuck 2 and stops movement of the master jaw 1 atthe desired point in its travel 6. At this point the soft jaw(s) 20 canbe formed to the desired shape for holding a workpiece during a latermachining operation.

It is noted that while examples are described herein with reference toimplementation on a lathe, that the chuck jaw stopping mechanism 10 maybe implemented on other types of machinery where a chuck 2 is used tohold a work piece, such as but not limited to, milling machines andgrinders.

In an example, the chuck jaw stopping mechanism 10 is located such thatthe soft jaw(s) 20 can be formed without interference on all the desiredsides of the soft jaw. The soft jaws can be formed on the inside all theway through for outside diameter clamping. The soft jaw(s) 20 can bebored on the face of the soft jaw for any diameter slug, and the outsideof the soft jaw can be turned for inside diameter clamping.

When the lathe chuck 2 is in the open position The stopping device 12 isclamped securely to the master jaw 1. There is a gap between thestopping device 12 and the outside diameter 3 of the chuck 2. When thechuck 2 is closed, the stopping device 12 will contact the outsidediameter 3 of the chuck 2 and stop so that the soft jaws can be formed.The stopping device 12 is fitted to the outside diameter of the lathechuck 2 and maintains the soft jaw in place for machining to precisespecifications. If there is more than one soft jaw 20 (e.g., mounted onseparate master jaws 1), all of the master jaws (and corresponding softjaws) stop evenly so that all of the soft jaws can be formed.

FIGS. 6-7 show the master jaws mounted in the chuck 2 with the soft jaws20 bolted on. An example workpiece 9 is shown for which the soft jaws 20will be formed to hold. The master jaw 1 fits inside the slot in thechuck body, and the T-nut 22 fits in another slot in the master jaw 1,as described above. The stopping device 12 is bolted and secured to themaster jaw via the T-nut 22.

The T-nut 22 fits into the master jaw 1 and is how the stopping device12 is attached to the master jaw 1, e.g., using the threaded portion ofthe modified T-nut 22. The clamping device 12 is held onto the masterjaw 1 using the threads in the T-nut 22.

The chuck 2 is assembled by the master jaw 1 fitting into the slot inthe chuck body. The T-nut 22 then slides into the slot in the master jaw1. Then the stopping device 12 is bolted into the threads in the T-nut22 to secure the stopping device 12 to the master jaw 1.

In an example, the stopping device 12 is secured to the master jaw 1while the chuck is in the open position. When the chuck 2 is closed, thestopping device 12 stops on the outside diameter 3 of the body of thechuck 2. When the stopping device 12 contacts the outside of the chuck2, the master jaw 1 and the soft jaw 20 is held in place so the softjaw(s) 20 can be formed.

The drawings show a chuck 2 implementing three soft jaws. But anynumber, size, shape, and configuration of soft jaws 20 may be provided.

FIG. 9 shows the example chuck jaw stopping mechanism 10 setup on alathe and ready for a soft jaw machining operation. It can be seen thatthe stopping mechanism 10 is located behind the soft jaw 20 for themachining operation. This enables unfettered access to the soft jaw 20so that the soft jaw 20 can be formed on the inside diameter, outsidediameter, and on the front face. With the stopping mechanism 10positioned behind the soft jaw 20, short and rigid forming tools can beused for the machining operation.

FIG. 10 shows the example chuck jaw stopping mechanism 10 setup on alathe of FIG. 9 after the soft jaw machining operation. The workpiece 9is shown as it may be inserted into the formed soft jaws 20 to be heldfor a machining operation on the workpiece 9. Any size or shapeworkpiece 9 may be implemented. The jaw stops travel a small distancebetween the open position (slightly away from the outside diameter ofthe chuck) and the closed position (touching the outside diameter of thechuck) of the jaws within the range of travel 6 of the master jaws 1.

FIG. 11 shows the example chuck jaw stopping mechanism 10 setup on alathe with the soft jaws 20 ready for a machining operation on aworkpiece 9. After forming the soft jaws 20, the jaw stops 12 can beremoved from the master jaws 1 and the lathe chuck is ready forproduction machining operations.

In an example, the chuck jaw stopping mechanism 10 can hold a workpiece9 with an extremely tight tolerance, maintaining a controlled distancefrom the face that locates on the master jaw 1 in relation to the facethat locates on the outside diameter of the lathe chuck 2.

The example chuck jaw stopping mechanism 10 works very well for thispurpose and saves a lot of time as compared to all other availableprocesses and devices. The chuck jaw stopping mechanism 10 may also beused in other work holding capacities, such as machining materials thatwould be deformed by standard work holding jaws. In addition, the chuckjaw stopping mechanism 10 can be modified to accommodate externalclamping in the boring process to allow for internal clamping on theworkpiece 9.

It is noted that the examples shown and described are provided forpurposes of illustration and are not intended to be limiting. Stillother examples are also contemplated.

The invention claimed is:
 1. A chuck jaw stopping mechanism for forminga soft jaw for a lathe, comprising: a stopping device; a securementdevice configured to connect the stopping device on a master jaw of achuck of the lathe; and a lower surface of the stopping device movingagainst a portion of an outer circumference of the chuck in a closedposition, and the lower surface moving away from the portion of theouter circumference of the chuck in an open position to form a gapbetween the lower surface of the stopping device and the portion of theoutside circumference of the chuck; and a T-nut to engage with themaster jaw and connect to the stopping device.
 2. The chuck jaw stoppingmechanism of claim 1, wherein the stopping device maintains the soft jawat a predetermined position within a range of travel during machining ofthe soft jaw.
 3. The chuck jaw stopping mechanism of claim 1, whereinthe stopping device stops inward movement of the master jaw at thepredetermined position for forming the soft jaw for holding a workpiece.4. The chuck jaw stopping mechanism of claim 1, wherein the gap enablesa workpiece to be inserted into the soft jaw after forming the soft jaw.5. The chuck jaw stopping mechanism of claim 1, wherein the securementdevice is a bolt that threads into a threaded opening of the master jaw.6. The chuck jaw stopping mechanism of claim 1, wherein the T-nutslidably engages and tightens to the master jaw.
 7. The chuck jawstopping mechanism of claim 1, wherein the stopping device connects tothe T-nut.
 8. The chuck jaw stopping mechanism of claim 1, wherein thesoft jaw is attached to the T-nut.
 9. The chuck jaw stopping mechanismof claim 1, wherein the T-nut has an extended portion, the extendedportion pulls toward the stopping device by operation of a fastener, theextended portion seating against the stopping device when the soft jawis located at a predetermined position within a range of travel of themaster jaw.
 10. The chuck jaw stopping mechanism of claim 1, wherein thestopping device holds the soft jaw without interference during amachining operation to form the soft jaw.
 11. The chuck jaw stoppingmechanism of claim 1, wherein the stopping device clamps the soft jaw onthe outer circumference of the chuck so that the soft jaw can be formedentirely through the soft jaw without clamp interference.
 12. The chuckjaw stopping mechanism of claim 1, wherein the soft jaws are machinableto receive any diameter of a slug without clamp interference.
 13. Thechuck jaw stopping mechanism of claim 1, wherein after forming the softjaw, the stopping device is removed from the master jaw and the chuck isready for production.
 14. A chuck jaw stopping mechanism for forming aplurality of soft jaws for a lathe, comprising: a plurality of stoppingdevices, each of the plurality of stopping devices corresponding to eachmaster jaw of a chuck of the lathe; a plurality of securement deviceseach configured to connect the stopping devices on the correspondingmaster jaws; and a lower surface of the stopping device moving against aportion of an outer circumference of the chuck in a closed position, andthe lower surface moving away from the portion of the outercircumference of the chuck in an open position to form a gap between thelower surface of the stopping device and the portion of the outsidecircumference of the chuck; and a T-nut to engage with the master jawand connect to at least one of the stopping devices, the T-nut slidablyengages and tightens to the master jaw, wherein the at least one of thestopping devices connects to the T-nut and the soft jaw is attached tothe T-nut; wherein each of the stopping devices uniformly stops thecorresponding master jaw for forming the soft jaws with the lathe. 15.The chuck jaw stopping mechanism of claim 14, wherein each of thestopping devices stop inward movement of the master jaw at apredetermined position for forming the soft jaw for holding a workpiece.16. The chuck jaw stopping mechanism of claim 14, wherein the T-nut hasan extended portion, the extended portion pulls toward the at least oneof the stopping devices by operation of a fastener, the extended portionmating with the at least one of the stopping devices to maintain thesoft jaw at a predetermined position within a range of travel duringmachining of the soft jaw.
 17. A chuck jaw stopping mechanism forforming a soft jaw for a lathe, comprising: a stopping device; asecurement device configured to connect the stopping device on a masterjaw of a chuck of the lathe; and a lower surface of the stopping devicemoving against a portion of an outer circumference of the chuck in aclosed position, and the lower surface moving away from the portion ofthe outer circumference of the chuck in an open position to form a gapbetween the lower surface of the stopping device and the portion of theoutside circumference of the chuck; wherein the stopping device has twoarms and the lower surface is formed on each of the two arms.
 18. Thechuck jaw stopping mechanism of claim 17, wherein the securement deviceconnects to the master jaw between the two arms of the stopping device.